"He is also a member of the Free Enterprise Group of MPs, and along with colleagues co-authored After the Coalition (2011) and Britannia Unchained (2012). The authors of Britannia Unchained claimed that "Once they enter the workplace, the British are among the worst idlers in the world".[11][12]"
I think a lot of his reasons are listed above but i think he's mainly angry that they get him to carry out a review of energy policy; he spent a lot of time and presumably political capital on it and then they've ignored it.